Wheel balance method



Oct. 28, 1969 F. J. BAGEMAN 3,474,679

WHEEL BALANCE METHOD Filed Nov. 25, 1966 MZAM/ff WWI/970.? .7/

' Mil/7641 INVENTOR. A'Pm J 5765/1414 Arum/16.

United States Patent 3,474,679 WHEEL BALANCE METHOD Fred J. Bageman, 52 Kings Court, Santurce, Pnerto Rico 00911 Filed Nov. 25, 1966, Ser. No. 596,973 Int. Cl. Gillm 1/02, 1/30 U.S. Cl. 73-483 1 Claim ABSTRACT OF THE DISCLOSURE A method of balancing automotive wheels in which a wheel to be balanced is laced horizontally upon a balancing machine, such as a bubble balancer, capable of indicating with accuracy the light spot of the wheel at which added balance weights are most eil'ective to balance the wheel. Provide at least two and optimally three sets of three balance weights, two weights in each set being of equal mass and the third weight having a mass double the mass of either of the other two weights. The weights increase in mass in selected increments from set to set. One set of weights is placed on the rim of the wheel so that the heavy weight of the set is at the light spot and the smaller weights are diametrically opposed to each other equidistantly from the wheel light spot. The smaller weights are moved symmetrically toward the light spot along the wheel rim until a condition of wheel balance is achieved. Then the small weights are connected to the wheel rim on the one side of the wheel at those locations corresponding to their adjusted positions at the time of balance, and the heavy weight is connected to the other side of the wheel in radial alignment with the light spot of the wheel. If the first set of weights has insufiicient mass to produce balance, the adjustment procedure is repeated with the second and, if necessary, the third sets of weights.

This invention relates to a method for balancing vehicle wheels, and has particular reference to a three-weight method for statically balancing wheels on a pivot point wheel balancing machine without upsetting the dynamic balance of the wheel.

Pivot point balancing machines are well known and are commonly found in tire stores and automobile service centers where wheel balancing services are offered to the public. The general concept is that when an automobile wheel, having a tire mounted to it, is placed at rest horizontally on the pivot point machine, any static unbalance of the wheel will cause it to deviate from the horizontal, as indicated by a bubble (spirit) level on the machine. conventionally, the wheel is statically balanced by the application of one or more small lead weights, called wheel weights or rim weights, to the rim of the wheel in a manner which causes the wheel to return to a horizontal plane and the bubble to center within the level. The place on the wheel at which the weight or weights should be applied is indicated in a general way by observing the highest point on the wheel rim when it is tilted from the horizontal by its unbalanced condition, this highest point being referred to as the light spot or point of maximum effectiveness of applied wheel weights. The light spot can also be located more accurately by observing the direction in which the bubble of the level is displaced from the center of the level. Each rim weight essentially is a piece of alloyed lead having a small steel clamp formed integrally with the weight. The clamp snaps over the rim of the Wheel when hit by a hammer.

This invention provides a method of balancing an automobile wheel on the type of machine described above with great accuracy yet without disturbing the dynamic balance of the wheel; practice of the method, in the vast majority of cases, reduces the effects of dynamic unbalance. Adherence to the method described herein eliminates entirely the inaccurate, inadequate and detrimental results of balancing procedures relying upon a single weight to achieve wheel balance; single-weight procedures require the maintenance of a large inventory of a large number of diiterent weights which vary progressively in size. Single-weight procedures inherently are inefiective to correct all static unbalance conditions encompassed by the multiple weight inventory, and such practices obviously change the dynamic balance of the wheel. The present method has no gaps relative to unbalance conditions below unbalance conditions which are so severe as to require corrective procedures going beyond the scope of techniques relying solely upon the addition of weight to the wheel. Also, the use of the present method reduces to a minimum the number of different weights which must be stocked to enable the balancing of the vast majority of unbalanced wheels. The method is characterized by its simplicity and reliability.

My United States Patent 3,085,442 owned by the assignee of the present invention, describes another threeweight method which is also effective to balance wheels efiiciently. While the procedure described in this patent may result in a quicker balance than the practice of the present method, this invention absolutely eliminates any possible chance that a wheel susceptible of being balanced by the addition of Weights will not be properly balanced.

Briefly, the present method includes the steps of positioning a wheel to be balanced, including a tire mounted to the wheel, horizontally upon a wheel balancing machine and measuring, with a high degree of accuracy, any deviation of the plane of the wheel from the horizontal, thereby to locate the point on the wheel adjacent the rim of maximum balancing effectiveness of balancing weights applied to the wheel. The method also comprehends placing adjacent the exposed rim of the wheel a set of three balancing wheel weights consisting of two weights of unit mass and one weight of twice unit mass and arranging the weights With the one weight at the point of maximum effectiveness and the two small weights diametrically opposed to each other across the wheel and on opposite sides of and equidistantly from the point of maximum effectiveness. The small weights are then positionally adjusted symmetrically along the wheel rim toward the point of maximum efifectiveness from their diametrically opposed initial positions. When a condition of balance is obtained, i.e., when the wheel returns to a horizontal position, the two small weights are connected to one rim of the wheel and the heavy weight is connected to the other rim at positions relative to the point of maximum effectiveness corresponding to the positions of the respective weights at the time balance is produced.

The above-mentioned and other features of the invention are more fully set forth in the following description of the invention, which description is presented with reference to the accompanying drawings, wherein:

FIG. 1 is a schematic elevation View of an automobile wheel resting on a conventional pivot point balancing machine;

FIG. 2 is a top plan view of the wheel on the machine; and

FIG. 3 is a schematic elevation view taken along line 33 of FIG. 2 showing the placement of rim weights on opposite sides of the wheel.

FIGS. 1 to 3 illustrate an automobile wheel having a tire 10 mounted on a wheel 12. The wheel has an outboard rim portion 14, an inboard rim portion 16, and a central aperture 18. The wheel rests on a conventional wheel balancing machine 20.

An upper portion of the balancing machine, which includes a balance indicator 21 usually in the form of a circular bubble level, extends through the central aperture of the wheel.

When the wheel is placed on the machine so that the plane of the wheel is in a horizontal position, any static unbalance of the wheel will cause the plane of the wheel to deviate from the horizontal. By observing the bubble level and the tilting of the wheel, the highest point of the wheel can be readily ascertained. This point is usually referred to as the light spot and is the theoretical position on the rim of the wheel where the application of a single weight of suitable size will bring the wheel into a perfect static balance such that the wheel returns to a horizontal position and the bubble 30 of the level indicator returns to the center of the level. The light spot is indicated in FIG. 2 by dotted circle 22. The wheel, theoretically, is divided into a heavy side and a light side by a neutral axis 23; the application of equal weights to the wheel at diametrically opposed locations along the neutral axis has no effect upon the static unbalance of the wheel. The wheel can be considered to possess a heavy spot 24 diametrically opposite from the light spot.

To balance wheel/tire combination 10, 12 according to this invention, a set of three rim weights 25, 26, 27 is placed upon the upper surface of the wheel on the tire just adjacent wheel rim portion 14. Weights 25-27 comprise one of at least two, and preferably three different sets of available weights and preferably is the least massive set of weights. Weights 25 and 26 are of equal size and weight and weight 27 weighs twice as much as either of weights 25 and 26. Weights '25, 26 are disposed at diametrically opposed locations along neutral axis 23, i.e., equidistantly from and on opposite sides of light spot 22, and weight 27 is disposed at the light spot, as shown in solid lines in FIG. 2. The light set of weights is used initially to assure that the tire will in fact be balanced if it can be balanced satisfactorily merely by the connection of rim weights to the wheel.

The balancing process is carried out by adjusting weight pairs 25, 26 symmetrically toward each other and the light spot along the wheel rim. As such movement occurs, the weights become increasingly etiective to balance the heavy spot on the opposite side of the neutral axis. This adjustment of the position of the small weights continues until the wheel is balanced; this state is indicated by the wheel assuming a horizontal attitude. The position of weights 25, 2-6 eflective to balance the wheel is depicted by the dotted line representation of the weights in FIG. 2. When the required adjustment of the weights is achieved, weights 25 and 26 are connected to wheel rim portion 16 adjacent, i.e., radially of the adjusted positions of these weights at equal distances from the light spot; weight 27 is secured to rim portion 14 adjacent the light spot.

Weights 25 and 26 can be connected to rim 14 and weight 27 to rim 16 if desired, but this arrangement is not preferred since it has been found that the most favorable efiect upon dynamic unbalance of the wheel results when the heavy weight is secured to the outboard rim of the wheel.

To achieve the best possible balance, it is preferred that the adjusted positions of weights 25 and 26 be marked on the tire tread with chalk. The wheel then is removed from the balancing machine, and weights 25 and 26 are applied to the inboard rim adjacent the chalk marks. The wheel is then returned to the balancing machine and the machine is used to provide a confirmatory indication of the perfectness of the balance when weight 27 is returned to its position on the wheel. If weights 25 and 26 were not secured to the wheel at exactly the proper positions, the balancing machine indicates this fact. It is necessary, then, to adjust weight 27 only slightly 4 along the wheel rim to achieve perfect static balance of the wheel.

If, however, the small weights of the first and lightest set of weights applied to the wheel must be moved to the light spot and still the wheel is unbalanced, then the next heaviest set of weights provided is selected and is placed as described above. The symmetrical adjustment process is then repeated until a balanced condition of the wheel is produced. The three weights are then secured to the inboard and outboard rim portions of the wheel in the manner described above. If all the weights of the second set can all be gathered at the light spot without overbalancing the wheel, the third set of weights is selected and the above-described procedure is repeated.

The second set of weights is constituted of two weights of twice unit mass and one weight of four times unit mass. The third set of weights is constituted of two weights of four times unit mass and one weight of eight times unit mass.

it all three weights of the third and heaviest set of weights can be collected at light spot 22 without balancing or overbalancing the wheel (a rare condition), it is known then that the wheel cannot properly be balanced merely by adding balance weights to the wheel; to balance such a severely unbalanced wheel, it is best to rotate the tire about degrees on the wheel and to recommence the above-described procedure.

To assure the best possible balance, the minimum amount of weight should be added to the wheel. The procedure described assures, consistent with the competing consideration that a minimum stock of weights should be inventories for economic reasons, that the least possible weight is applied to an unbalanced wheel to achieve balance, and this is also economically important. Also, the procedure described assures that the wheel will be balanced if it can in fact be balanced safely, that is, the procedure described does not skip any weight arrangement effective to balance the wheel as is the case with procedures which rely upon a single Weight to perfect balance. Because the weights used to accomplish balance are equally distributed on opposite sides of the wheel, the dynamic balance of the wheel is essentially undisturbed and the effect of any dynamic unbalance in the wheel is reduced in the vast majority of cases.

What is claimed is:

1. A method for balancing an automobile wheel having a tire mounted thereto comprising the steps of positioning the wheel horizontally upon a wheel balancing machine, measuring with a high degree of accuracy any deviation of the plane of the wheel from the horizontal thereby to locate the point on the wheel adjacent the rim thereof of maximum balancing effectiveness of balancing weights applied to the wheel, providing three sets of balancing rim weights, the first weight set consisting of two weights of unit mass and one weight of twice unit mass, the second weight set consisting of two weights of twice unit mass and one weight of four times unit mass, the third weight set consisting of two weights of four times unit mass and one weight of eight times unit mass, placing the first weight set on the wheel rim and arranging the weights thereof with the one weight at the point of maximum efiectiveness and the two weights disposed diametrically opposite each other equidistantly from and on opposite sides of the point of maximum effectiveness, adjusting said two weights symmetrically along the rim toward the point of maximum effectiveness from their positions of diametric opposition until the wheel is balanced, removing the first weight set from the wheel and repeating the placing and arranging step and the adjusting step with the second weight set if the first weight set is ineliective to produce a condition of balance when the weights thereof are collected at the point of maximum effectiveness, removing the second weight set from the wheel and repeating the placing and arranging step and the adjusting step with the third weight set if the second weight set is inefi'ective to produce a condition of balance when the weights thereof are collected at the point of maximum etfectiveness, and connecting the two weights of the set which produces balance to one rim of the wheel and the one weight of the same set to the other rim of the wheel at positions relative to the point of maximum effectiveness corresponding to the positions of the respective weights at the time balance is produced.

References Cited UNITED STATES PATENTS JAMES J. GILL, Primary Examiner 

